@function dpiRatio($a) {
  @return calc($a / 3);//math.div($a, 2);//$a / 2
}

@function dpi($a) {
  @return calc($a / 3);//math.div($a, 2);//$a / 2
}

@mixin addwh($width, $height:$width) {
  width: dpi($width);
  height: dpi($height);
}